Solving North India's air quality crisis

North India faces a difficult situation on air quality, and this has adverse implications for the health of 600 million people. It is entirely feasible for policymakers to solve this problem. A key tool is source attribution: Apportioning the dust in the air to the underlying sources. This data capture in India is, at present, inadequate. There is significant evidence that crop burning in Punjab and Haryana was influenced by intrusive state laws enacted in 2009 for the purpose of water conservation. Crop burning in these states rose sharply after 2009. The two states need to repeal these laws.

With the Himalayas in the north and the Deccan plateau in the south, the Gangetic plains of North India are like a bowl. After the monsoon subsides, there is little wind and rain. As a consequence, when dust is injected into the air, it tends to linger. In the last decade, human activities injected more dust into the air as compared with what was prevalent before and generated a health crisis.

Four of the five most polluted cities in the world are in the Indo-Gangetic plains. Low air quality is not just a problem in terms of respiratory illness; it triggers a host of other kinds of harm to human health, including the exacerbation of the deteriorative illnesses of old age. As the Indo-Gangetic plains contain 600 million people, the deterioration of air quality over the last decade has shaped up as a significant health crisis. One of the top priorities of health policy in India is to get back to the air quality of 15 years ago.

We cannot change the wind and rain, we can only change the human activities which are injecting dust into the air. The most important question about the dust in the air is that of understanding where it comes from. This is done using “source apportionment studies”, which consist of capturing a sample of air and deciphering what is in it. Such studies are done continuously in cities all over the world. In India, one such study was done in 2014-15. This lack of data has hampered understanding and action.

China was famous for its terrible air quality. But it has made progress. As an example, in the last two days, the PM2.5 for Delhi ranged between 158 and 565, while in Beijing it ranged from 109 to 184. The establishment of the statistical infrastructure, of continuous source apportionment, was an important element of how the Chinese obtained gains on their air quality crisis.

The lack of continuous source apportionment has generated model-based estimates and confusion about understanding and solving the North Indian air quality crisis. But it is important to see that only about 15 years ago, air quality in North India was much better; something happened in this period which triggered the air quality crisis. What changed?

An important paper on this was published by Balwinder Singh and co-authors in Nature Sustainability in June 2019. The authors report that in 2009, Punjab and Haryana enacted new laws (“Preservation of Subsoil Water Act”) aimed at improving water conservation. These laws gave the government the power to define a precise date prior to which farmers are prohibited from transplanting paddy from the nursery. Such laws are a bad idea in terms of economics and public policy, as the government should not be intrusively involved in the private choices of farmers. Such heavy-handed intrusion tends to induce unintended consequences.

Illustration: Binay Sinha

Farmers have argued that the policy actions of the state governments have reduced the number of days available between the kharif and rabi crops, and created incentives to burn the stubble in order to rapidly clear the field. While the health statistics system in India is weak, the researchers are able to measure crop burning using satellite imagery and are able to augment the data on PM2.5 from ground-monitoring stations with satellite-estimated PM2.5, and thus examine the changes which took place around the enactment of new laws in 2009.

The researchers demonstrate that the new laws kicked off a surge in crop burning. They also shifted the date of the peak burning from October 24 to November 4, which is a time when temperatures are lower and the winds are weaker. This gave a 29 per cent worsening of air quality.

If the laws of 2009 kicked off an air quality crisis, the best way forward for policy lies in going to the root cause and repealing these laws. There are surely myriad other mechanisms through which water conservation can be improved, and experts on agriculture can find these. There is surely a need for light-touch intervention rather than the central planning vision of using the coercive power of the state to order farmers about precise dates on which certain economic activities should be undertaken.

As 11 years have gone by, clean air in North India is increasingly a distant memory. We must not lose heart; such problems are highly solvable, given the right intellectual capacity. There are numerous countries where air-quality problems were faced, and through sound intellectual work, solved. As an example, an article by David Parrish and co-authors in Atmospheric Environment, in 2011, about Los Angeles says, “It is fair to say that this mega-city has gone from being one of the most polluted in the world 50 years ago to presently one of the least polluted cities of its size.”

For India today, two lines of work appear attractive. The first consists of establishing a sound statistical system on air quality, and a community of researchers. The second consists of repealing the offending 2009 laws in Punjab and Haryana. Punjab and Haryana should see their self-interest in such a repeal, as the bad air influences the health of their people. In addition, there is a need for mechanisms through which other states are able to demand compensation from Punjab and Haryana.

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